Hi All,

I need some clarification on a Cisco VIC configuration.

Hardware in use:
Cisco VIC 15427 – 4x 10/25/50G mLOM (C-Series)

This environment is in UCS Managed (UCM) mode, with Fabric Interconnects uplinked to the network.

Customer is complaining about replication delays with an Oracle database.
When I checked the OS side (Linux), the NIC is showing a speed of 50000 Mb/s = 50 Gbps — but at the same time, the customer says that in their old system (DX1), the NIC was running at 20 Gbps and performance was better.

So I’m trying to confirm:

1) Is this “50G” real line speed, or is this just what is being advertised to the OS?

Is there any possibility that the actual speed / policy / QoS / network class is limited somewhere at UCS policy level?
Or could the FI uplink or vNIC template be restricting throughput even though OS reports 50G?

2) Regarding the Resource / Queue settings (screenshot below)

Are these default recommended values from Cisco for VIC 15000-series cards?

Should these be tuned for high throughput replication workloads (Oracle – async replication)?

I’m still relatively new to VIC tuning, so I want to make sure I am not missing anything
Just want to validate whether this interface is really operating at the expected bandwidth, or if there is any policy-side limitation in UCS that could explain the observed replication delay.

Any guidance / best-practice pointers from people who have tuned VXLAN / IP replication links on VIC 15000-series in UCSM mode would be very helpful.




VIC 15427 – OS Reports 50G, But Performance Feels Lower — How to Validate Real Throughput?